[gdb] Fix more typos

Fix some more typos:
- distinquish -> distinguish
- actualy -> actually
- singe -> single
- frash -> frame
- chid -> child
- dissassembler -> disassembler
- uninitalized -> uninitialized
- precontidion -> precondition
- regsiters -> registers
- marge -> merge
- sate -> state
- garanteed -> guaranteed
- explictly -> explicitly
- prefices (nonstandard plural) -> prefixes
- bondary -> boundary
- formated -> formatted
- ithe -> the
- arrav -> array
- coresponding -> corresponding
- owend -> owned
- fials -> fails
- diasm -> disasm
- ture -> true
- tpye -> type

There's one code change, the name of macro SIG_CODE_BONDARY_FAULT changed to
SIG_CODE_BOUNDARY_FAULT.

Tested on x86_64-linux.

gdb/cli/cli-decode.c

@@ -1779,7 +1779,7 @@ help_cmd (const char *command, struct ui_file *stream)
 
   if (alias == nullptr || !user_documented_alias (*alias))
     {
-      /* Case of a normal command, or an alias not explictly
+      /* Case of a normal command, or an alias not explicitly
 	 documented by the user.  */
       /* If the user asked 'help somecommand' and there is no alias,
 	 the false indicates to not output the (single) command name.  */
@@ -1789,7 +1789,7 @@ help_cmd (const char *command, struct ui_file *stream)
     }
   else
     {
-      /* Case of an alias explictly documented by the user.
+      /* Case of an alias explicitly documented by the user.
 	 Only output the alias definition and its explicit documentation.  */
       fput_alias_definition_styled (*alias, stream);
       fput_command_names_styled (*alias, false, "\n", stream);